SAN FRANCISCO - DECEMBER 9: Running back Adrian Peterson #28 of the Minnesota Vikings is hit by linerbacker Patrick Willis #52 of the San Francisco 49ers during a game on December 9, 2007 at Monster Park in San Francisco, California. Minnesota won 27-7. (Photo by Greg Trott/Getty Images)

Photo: Greg Trott, Getty Images

SAN FRANCISCO - DECEMBER 9: Running back Adrian Peterson #28 of...

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FILE -- This is a Sept. 20, 2009, file photo showing Minnesota Vikings running back Adrian Peterson running against the Detroit Lions in the second quarter of an NFL football game, in Detroit. San francisco 49ers Frank Gore watched the highlights of his two long touchdown runs from Sunday so many times that he finally turned the channel. "I kinda got tired of watching the same thing over and over," he said. Now he knows how Minnesota's Adrian Peterson must feel every Sunday. (AP Photo/Paul Sancya, File)

Though a linebacker by trade, Willis appreciates the way Peterson runs the ball. With Willis calling the plays on Madden, Peterson gets more than his share of carries.

"He's what you want your running back to be," Willis said in an interview with The Chronicle. "When I play Madden, I want to know I have a ground game. I'm old-school. I like the run. The strategy is still the same. I like the run. My running sets up the passing. That's football. If you can't stop the run, you keep running."

In his day job with the 49ers, however, Willis will be doing all he can Sunday at the Metrodome to stop Peterson from running the ball, or at least running wild with it.

In addition to being the only game on the NFL's Week 3 schedule featuring undefeated teams, Sunday's 49ers-at-Vikings contest also has, for enhanced viewing pleasure, the best linebacker in the league going after the best running back in the league.

Don't expect any trash talk from either Willis or Peterson in the build-up to the game. Both are respectful young men who admire how the other plays the game. To Willis, Peterson is a "beast." To Peterson, Willis is a "freak."

"I have the utmost respect for Adrian Peterson," Willis said. "I respect what he's done for the game. He's a beast, any way you look at it. We have our work cut out for us."

On a Wednesday conference call from Minnesota, Peterson recalled a Dec. 9, 2007 game against the 49ers at Candlestick Park as the worst of his career after he gained 3 yards on 14 carries and averaged 0.2 yards a try. He described the 49ers' defense as being like a swarm of bees and had a special designation for king bee Willis:

"He's got that deadly sting. I love Patrick Willis, man. I love the way he plays ball. He plays ball just like me. He's the best defensive player in the league at his position - not to take anything away from Ray Lewis; I think eventually he will be better than Ray Lewis."

Willis and Peterson are, in many ways, mirror images of each other as players. They are both 24, in their third year, were chosen in the top half of the 2007 draft and are equally accomplished. Willis was the NFL's defensive rookie of the year in '07 while Peterson was the league's offensive rookie. Each man began his career by making back-to-back Pro Bowls.

Furthermore, each man said he would play like the other were he on that side of the ball, Willis as a running back and Peterson as a linebacker.

"I ran the ball in high school a lot," Willis said. "That's the way I like to run the ball. You take what they give you. When you have to make something happen, you make it happen. That's why I respect his game. He can do it all."

For his part, Peterson, the league's leading rusher, said, "I think we play the game with the same passion. He's a freak. He's 245, (runs a) 4.3. He's a perfect prototype for a linebacker."

Willis and his defensive mates got the better of Peterson in 2007 but with five turnovers on offense, the 49ers had no chance to win the game. Although he was on the winning side, Peterson is haunted by how he was corralled by the 49ers.

"That's a game that sticks in my mind," Peterson said. "It's the worst game of my career. I don't take it lightly. I give praise to San Francisco's defense. They have some good guys. They play football like football should be played on the defensive side of the ball. I felt like I was being attacked by bees in that game."

Four weeks earlier in '07, Peterson had established an NFL single-game record for rushing when he punished the San Diego Chargers for 296 yards on 30 carries. He finished his rookie season with 1,341 yards and followed up with 1,760 last year.

In his rookie season Willis led the NFL in tackles with 174 and had one 20-tackle games and nine others in which he had at least 10 stops.

Willis the freak is every bit as productive on defense as Peterson the beast is on offense. How nice the two chaps get to tee it up Sunday.

There will undoubtedly come a moment in the Metrodome when Willis finds himself one-on-one with Peterson, his ideal video game running back. What then, Patrick?

"I'm going to think what I think on any play: it's either him or me," Willis said. "Any running back on any given Sunday can get the best of you. But I want to get the best of whoever is in front of me. My mentality is, it's either me or you."